Radio traffic signaling system



Oct. 28, 1947.

FIGA.

W. H. CAPEN RADIO TRAFFIC SIGNALING SYSTEM Filed March 14, 1940 7Sheets-Sheet l TRANSMITTER rm/vsmrrsn n02 3 O Q I l '1 RADIATOR RECORDAMPLIFIER F AND AND zmawcm aauuumn I l RADIO TRAFFlgMfiG/MLFREQUENCY--44 AM some:

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Oct. 28, 1947.

w. H. CAPEN 2,429,607

RADIO TRAFFIC SIGNALING SYSTEM Filed March 14, 1940 'T Sheets-Sheet 2[as/mail FILTER l CARRIER Z1 29 25 sou/ace 1 l man 27 28 FREOUENcr I%MEf|' muLfi FILTER Sal/R05 FREOl/EMV sum:

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33 35 PL/FIER FILTER ---0 34 R0012? 31 Hum '33 I INVENTOR.

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Oct. 28, 1947. w. H. CAPEN 2,429,607

RADIO TRAFFIC SIGNALING SYSTEM Filed March 14, 1940 7 Sheets-Sheet 3GENERAL I 3 ZTRAF7/Co 30 con/o 7/ iv:

V DEMODULATflR DETECTOR AMPLIFIER FILTER ROI/7E3 rmw n/rmvs 98 RECEIVERINVENTOR. WILL/AM H CAPE/V AT 0/ NEY.

Oct. 28, 1947. w, cAPEN 2,429,607

RADIO TRAFFIC SIGNALING SYSTEM Filed March 14, 1940 7 Sheets-Sheet 4NFRA-RED LIGHT -50 CONTROLS CONTROLS ro PLI T0 MODULATED 221m CURRENTSOURCE TRANSMITTERs ROUTE *1 INV EN TOR. MIL/AM H. CAPEN Oct. 28; 1947.w, cAPEN 2,429,607

RADIO TRAFFIC SIGNALING SYSTEM Filed March 14, 1940 7 Sheets-Sheet 5HOUSING MITTER 60 E nsmowczj T0 TRANSMITTING AHPLIFIE MPLIFIER oouau: 63-l T0 LAMP T0 AMPUFIEM INVENTOR. W/ZL/AM H. C'APEN AT NEY.

Oct. 28, 1947. w, c p 2,429,607

RADIO TRAFFIC SIGNALING SYSTEM Filed March 14, 1940 7 Sheets-Sheet 6 REPODUC\ER$ RECORD MONITOR '71 mwsnn' 11 RECORD\ T0 INTERLOCKED ban/"cutsGROUP SELECTM REPRODUCER REPRODUtE/RS F6 To sascrons GROUP /77 JUNCTION*1 *1 2 3 SELECTOR uge mu l J re Jamar/av? 2 "1 '2 "3 can/ma CENTER LINVENTOR. t mu [AM H. O4PN AMPLIFIERS 1 2 -3 4 I a/ T0 RADIATING MEANSATT EY.

Oct. 28, 1947. w, CAPEN 2,429,607

RADIO TRAFFIC SIGNALING SYSTEM Filed March 14, 1940 7 Sheets-Sheet 7JUNCTION con/mm CENTFWSELECTUR 20.

I l -J L ,7 GROUP W GROUP GROUP sELEcron SELECTOR SELECTOR pup T0REHMDUCER FIG 2 92 SELECTOR-S JUNCTION CONTROL CENTER sELEcToR I I I JT0 AMPLIFIERS GROUP cRol/P GROUP SELECTOR SELECTOR SELECTOR AMPLIFIE T0RE IPODUCER SELECTOR SELECTO ----I TO REPRgDUCE/i' \S'ELECTORS 0PEmT/av-U0 OPE/PAT/ON JELEcToRS T0 AHPL/F EH5 MPLIF/ER J T0 RADM TING MEANSGROUP REPRODMZ'ER E m 1' INVENTOR. s R WILL/AM H. CAPE/V \LAMP GROUPSELECTORS 1/ T0 GROUP sELEcTons AT J UNCT IONS ATT Patented Qct. 28,1947 .RADIO TRAFFIC SIGNALING SYSTEM William H. Capen, Mountain Lakes,N. J., assignor to International Standard Electric Corporation, NewYork, N. Y., a corporation of Delaware 1 Application March 14, 1940,Serial No. 323,883

This invention relates to arrangements for providing audible signals onautomobiles and more specifically to arrangements for providing audiblesigrlials on automobiles for purposes of trailic con- Traflic on thehighways is becoming more and more congested and cars are being drivenat increasing speed. Multiple lane super-highways are being built andcomplicated clover leaf and other confusing intersections are increasingin number. All routes, whether simple low speed twolane roads,complicatedmulti-lane express highways, or intricate city streetintersections, are today marked only by visual signs giving routenumbers or destinations.

It is very difficult for a car driver to quickly see these signs, andthe driver is often confused by trafilc signals of the visual type. Inorder to learn which way to go, which way to turn, the driver notfamiliar with his surroundings must take his eyes from the road and seeka sign for his guidance. Sign hunting at intersections also slows downthe particular driverwho is searching for his routes and necessarilyslows down the cars following him. This usually results in unnecessarypassing of one car by another. Both of these actionsare extremelydangerous and result in many collisions and needless deaths and injurieseach year.

All of these difliculties can ,be overcome by transmitting audiblesignals to the driver. In accordance with one embodiment of myinvention, radio frequency energy is transmitted by means of specialradiators along the route followed by an automobile. This energy ismodulated by traffic or route direction signals, under control of soundrecords, for example, and a receiver 'on the automobile receives themodulated energy and transforms it into audible signals. In accordancewith another embodiment of my invention energy at audible orsuper-audible frequencies is transmitted to an automobile and receivedtherein. Another embodiment of my invention utilizes infra-red light fortransmitting trafllc directions to an automobile.

With installations of the above kind, in accord ance with my invention,there is normally more than one radiating source at each intersection.

16 Claims. (Cl. 177-337) radiating point and apparatus for connectingall of the points to a central controlling station,

' My invention will be more clearly understood by reference to theattached drawings wherein:

Fig. 1 is a representative arrangement of the transmitting sources of myinvention;

Fig. 2 illustrates the circuit arrangement of a transmitter of the typeshown in Fig. 1 and a receiver for use on an automobile;

Figs. 3 and 4 are modifications of the receiver shown in Fig. 2;

Fig. 5 shows in elevation, and Fig. 5a is a plan view of an ultra-highfrequency radiator for directing radio frequency energy in accordancewith my invention;

Fig. 6 shows a modification of the transmitter 'and receiver of Fig. 2whereby route selection of infra-red light;

Since there are numerous intersectionsand several radiators, it isdesirable to tie one radiating vention is further concerned with meansfor easily changing the trafiic directions given out by each system;

Fig. 12 shows transmitting and receiving lamps for use with the systemshown in Figs. 11 and Fig. 13 illustrates a typical arrangement ofroutes and distribution of transmitters of my invention; l

Figs, 14 through 17 illustrate manual switching arrangements forchanging the tramc directions transmitted to an automobile and formonitoring the transmitters giving out said direction;

Fig. 18 shows a circuit arrangement for remote- 1y controlling thetransmitters at the various route or street intersections;

Fig. 19 illustrates the circuit construction of relays for use in aremote control system of Fig. 18;

Figs. 20 and 21 illustrate modifications of the remote control system ofFig. 18;

Fig. 22 illustrates a map and-pilot light arrangement forindicating theoperating conditions of the transmitters in a-remotely controlled Fig.,23 shows a circuit arrangement for si- 3 multaneously operating thepilot lights of Fig. 22 with the remote control system of Fig. 18.

As shown in Fig. 1, when two highways cross there are four ways toapproach the intersection.

It is possible to transmit directions to vehicles approaching thisintersection by a si gle transmitting sourc and means to identify thedirections intended for the different vehicles by vehicles going south,etc. However, a system of this sort is somewhat confusing and tendstowards complexity rather than simplicity, a primary object of thisinvention. According to one embodiment of my invention I employradiators having different di'rectivities or radiators whose energy isrestricted to a single roadway and to automatically or manually switch atransmitter from one radiator to another. While this latter system hasan economic advantage, it is desirable to transmit traffic directions toall roadways continuously and simultaneously.

According to a preferred embodiment of my invention, therefore, Iprovide four separate transmitters I, and associated radiators I,extending along the various roadways. Although I hav shown the fourtransmitters at separate locations, it is possible that the transmittersmay be included in a single housing and wires provided to lead theirrespective energies to the proper transmitting or radiating point.

At intersections where the tramc is congested and/or automobiles mustproceed at a moderate rate of speed, the radiators are preferablylocated a few hundred feet from the intersection, and if the radiatorsare located along high speed highways, the spacing of the radiators fromthe intersection may be conveniently calculated. Suppose, for example,the average announcement takes about ten seconds. This announcementshould be repeated three times to a motorist, and with an automobilespeed of 60 miles per hour-=88 feet per second, the automobile should bein the range of the radiator for a distance of 30x88=2640 feet, orone-half mile. The motorist should be warned of the route or roadchanges about one-quarter to one-half mile before reaching theintersection. Assuming a radiator range of one-half mile and a warningdistance of one-half mile before the intersection, the radiator wouldthen be spaced one mile from the intersection. These figures are, ofcourse, purely hypothetical and are given to illustrate the method ofdetermining the radiator spacing from the road intersection. This typeof calculation may be extended to meet any set of conditions.

Under normal operating conditions, the directions given over a period oftime will be a continuous repetition of this desired information andthese directions may therefore be given out by a mechanical device. Adisk type record with a repeating arrangement on the reproducer arm or asound on film reproducer may be used, but the preferred reproducer for asystem of this type is a reproducer of a well known type wherein voiceor other signals are recorded electromagnetically on a wire or tape ofmagnetic material, the signal being retained in the form of variablymagnetized areas of the wire or tape. This arrangement has the advantagethat the recorded signals may be erased or wiped off by running therecord medium through a magnetic field thus making it possible to use itfor other recordings. Such an arrangement is disclosed in Patent No.661,619, issued to Poulson, November 13, 1900.

A transmitter having a mechanical announcing device and a receiver areshown in Fig. 2, in this 4 e figure a rcproducer 3 controlled by arecord modulates a radio frequency source 4 in the amplifier andmodulating stage 5. The amplifier and modulator 5, preferably of a lowpower type so as to restrict the radiation to a small area, feeds theradiator I which may be one or more cables buried in the roadway andrunning parallel therewith, a network of conductors in the roadway, or aradiator at the side of the road either on the ground or mounted onpoles.

Since many broadcast receivers are already installed on automobiles, myinvention will be most readily adapted to the present equipment byradiating the tramc direction signals at very low power at radiofrequency. In this case the antenna already provided may be used to pickup the trafllc signals -or an auxiliary antenna may be installed in amost advantageous position in the automobile, such as, for example,under the chassis close to the roadway. The frequency at which thetraffic signals are to be radiated is preferably standardized and whenthe driver of an automobile desires to receive trafllc signals,

it is merely necessary to tune his set to a definite frequency or tothrow an auxiliary switch which brings into operation a circuit tuned tothat frequency. Alternatively, a separate antenna may be provided whichis connected directly to the intermediate or detector stages of thereceiver, or the radiating frequency may be made equal to. theintermediate frequency, and automatic switches provided which willdisconnect the broadcast signals and allow the tramc to enter theintermediate stages directly. A manual switch or automatic switch laterdescribed in detail, included in the receiver or antenna circuit, maybeprovided to chang the receiver over from broadcast reception to trafilcsignal reception.

The transmitted signals may be transmitted at any predeterminedfrequency and a separate tuned or variable receiver installed on anautomobile. If the frequency used for transmitting the tramc signals isoutside the rangeof the ordinary broadcast receiver, it is not necessaryto install an entirely separat receiver. To reduce the cost of theinstallation the traillc signals may be received on an antenna 8 asshown in Fig. 3, passed through a demodulator 9 and fed to thefinal'amplifler stage of the broadcast receiver. A switch Ill allows thereceiver output to be easily changed over from broadcast to traflicsignals.

Afurther convenience for changing over from broadcast signals to trafilcsignals is shown in Fig. 4. When no trafiic signals are received. arelay armature II is in a rest position, as shown,

, and connects the detector stage of the broadcast receiver to the finalamplifier stage. Under these conditions, the ordinary broadcast signalsare emitted in audible form from the speaker l2. When trafilc signalsare received on the antenna 8, these signals are detected anddemodulated by demodulator 9; these signals then pass through anamplifier i3 and rectifier ll. The output of the rectifier M, which maybe of the dry type, controls a relay coil i5 which operates to pull therelay armature ii to the right against contacts l6 and II. In thisposition the output of the demodulator 9 is connected to the final amplifier stage of the receiver, and trafiic signals are emitted in audibleform from the speaker l2. It is apparent that the relay coil I! may beswitched in or out of operation, dependent upon the will of the driver.

The energy radiated may be ultrahigh frequency energy. In this case ahorn or guide it may be located beside the roadway as shown in Fig. 5 ormounted on poles or cables overhanging the roadway. These horns orguides concentrate the energy into a very narrow beam at a shortdistance away from the source and hence with an arrangement similar tothat of Fig. 1 one field of energy will not overlap a second fieldtransmitting diflerent signals. The horns ,or radiators may be connectedto their source or sources by any well known means such as dielectricguides. To further avoid interference the antenna l9 located on theautomobile may be made highly directive, so that signals comingsubstantially only from in front of the automobile will be received.

A driver approaching an intersection may be interested in only a singleroute, and if the intersection is the-junction of several routes, theidentity of the driver's desired route may be lost in the mass ofinformation given. To clearly dis- I tinguish one route from another theinformation concerning each route may be transmitted on a diiferentfrequency. If the frequency for a given route is standardized throughoutits length the driver keeps his receiver tuned to the frequency of theroute desired, and as he progresses, he will receive informationconcerning only the route along which he is traveling.

source 23 in a modulator H2. This first reproducer 28 may contain arecord or tape giving directions or information concerning minor routes.A second reproducer 25 having a. record giving information of a majorroute or major routes. modulates a carrier frequency source 26 at amodulator 21. The output of this modulator 21 after passing through afilter 28 modulates the high frequency source 23 simultaneously withthat from 22 at the modulator H2. The combined output from N2 is fed tothe radiator 29. Other reproducers may also be provided so that eachreproducer gives information concerning only one route.

At the receiving end an antenna30 receives the trafllc signals and feedsthem to a first detector 3I which demodulates the radio frequenc energyand produces the combined modulated sub-carriers. The output of thefirst demodulator 3| is connected to a group of band-pass filters 32 and33. Filter 32 passes the modulated energy carrying the general routeinformation, and filters 33 each pass a band of frequenciescorresponding to the frequencies of the modulated carrier giving theinformation concerning only a single route. The output of the filters 33connect to a selector switch 34, which in turn connects to contact point35 and amplifier-rectifier 36. The amplifier-rectifier 36 controls arelay coil 31. When the special route signals for the route on whichroute switch 34 is set are below a given predetermined level, relayarmature 38 is at a rest position contacting point 39. In this positionthe output of filter 32 is connected to detector 48 which demodulatesthe carrier into audible signals at the speaker 4|. When the specialroute signals are above a predetermined level, the output of one of thefilters 33 is connected through contact point 35 and armature 38 to thedetector 48, and hence only signals presenting the particular routeselected will be heard at the speaker 4!. Thus when approaching anintersection where special route signals are being sent out only thesesignals for the route corresponding to the setting of switch 34 will beheard.

The same carrier frequency may be used several times for differentindividual route information as long as any two routes using thiscarrier do not intersect. A chart or schedule could be published givingsettings or designations of the filters for radio routes throughout alarge area.

Hence to follow a desired route it would only be necessary to set theautomobile receiver equipment to the proper designations and all routeinformation and important instructions will be received automatically.

If it is desired to avoid interruption of the general trafllc signals inthe receiver arrangement of Fig. 6, a slow-acting relay 93 and arectifier may be added to the output circuit of detector-amplifier 48 asshown in Fig. 7. When general trafllc signals are received throughfilter 32 and detected at detector-amplifier 48, relay 93 holds thecircuit of coil 31 open so that individual route signals passing throughone of the filters 33 will not interrupt the general traffic signals byoperation of relay 31. If there is a short pause after each transmissionof general trafllc information, relay 93 releases and the circuit ofcoil 31 is closed. Route signals from one of the filters 33 will thenoperate relay 31-38 transferring the input of the. detector-amplifier tothat filter. To prevent operation of relay 93 by the individual routesignals a contact 94 is added to relay 31. The circuit through contact94, however, is broken slightly ahead of the making of the circuitcontrolled by armature 38 and its contact 35, and therefore relay '93cannot be operated by individual route signals; When the individualroute signals are discontinued. relay 31 releases and contacts 39 and 94are closed, and the receiver is again ready for reception of generaltraffic signals.

The transmitting apparatus may be located at points where there isinsufiicient traflic to justify continuous operation of the apparatus,and since all automobiles may not be equipped with trailic signalreception apparatus, it would not be economical to transmit the signalsto all automobiles. I have therefore provided a remote control system asshown in Fig, 8 to switch on the transmitting apparatus when anautomobile provided with suitable reception equipment approaches atransmitting point. A transmitter 95, which may be of small low-powertype, located on an automobile having trafiic signal receivingapparatus, transmits energy to the receiver 96, the output of whichcontrols relay 91. The receiver 95 is preferably located near the sideof the road and some distance ahead of the transmitting apparatus 98 inorder to reduce the power requirements of transmitter 95 and to startthe transmitter before the automobile enters the signal zone. Contact 99shorts the lines I88 which interconnect the receiving and transmittingpoints and thus energizes relay coil I8I. Arm I82 moves to the leftagainst its contact closing the power circuits of the driving motor I 83and transmitting apparatus 98. If desired, a delayed switching circuitmay be employed to switch on the transmitter power and allow it to warmup before switching on the motor I83, and other controls 7 or contactssuch as a motor clutch, etc. may be added to operate, simultaneouslywith the arm I02. A wheel I04 which is part of the transmitterreproducer mechanism preferably rotates once for each completetransmission by the record containing the traflic information and holdsthe arm I02 against its contact during the record transmission, andafter an automobile transmitter passes out of range of receiver 00 thecoil III is deenergized. After one complete revolution of the wheel thearm I02 opens the power circuits and the apparatus is ready for the nextset of signals from an automobile.

If a second automobile passes the receiver 00 just before the arm I02drops into the wheel slot, it will receive only a portion or none of thetraffic signals. Two or more spaced receivers along the signal zone maythen be employed .so that if a following car has passed out of range ofthe first control receiver one of the other receivers will be actuatedto hold the arm I02 out of the slot and against its contact and insurethat a second automobile will hear the directions, the transmitternormally repeating the same directions two or three times for eachrevolution of wheel I04. Alternatively the arrangement of Fig. 9 maysupplement the parts in Fig, 8. A cam I05 is attached to the shaft ofwheel I04 and has a periphery that corresponds to the portion of thewheel revolution required for the transmission of a series of trafilcsignals. Suppose, for example, three repetitions of signals aretransmitted for one revolution of wheel I04. Then. the periphery of camI05 is substantially 120, not allowing for mechanical taper. If anautomobile having a transmitter passes the receiver 90 of Fig. 8 toolate in the transmission period to receive a complete set of trafficsignals, the impulse received at receiver 95 energizes coils I01 and IN.The energization of coil I 0| has no effect during the motion of wheelI04, but coil I01 closes contact I00. Since this energization occursduring the transmission of the last series of signals, cam I05 hasclosed arm I 00 against contact I00 thereby shorting lines I00 andenergizing coils I01 and IN from source IIO. When the slot is in frontof the projection on arm I02, the power circuits do not open because armI02 is held against its contact (or contacts) by the energized coil IN,and the transmitting apparatus repeats its cycle. After the slot haspassed by the projection on arm I02, cam I05 opens the holdingcircuitbyallowing arm I05 to drop away from contact I09 and hencecontact I08 also opens. When the transmitting apparatus is idle and animpulse at the receiver energizes coils I01 and IOI, the holding.circuit does not act to repeat the transmitting cycle since the holdingcircuit is opened by cam I05 during the first portion of a transmittingcycle. The length of periphery of cam I05 may, of

course, be changed to meet the requirements of the length of a set ofsignals, orto change the number of sets transmitted to a secondautomobile.

Since the energy carrying the trafllc signals is to travel only a shortdistance, it is possible to use electromagnetic energy of audible orsuperaudible frequency, or alternatively the signals may be transmittedand received by well known acoustic means using supersonic frequencies.An arrangement of the electromagnetic type is shown in Fig. 10. Theinformation to be given out is spoken into the microphone 42 or recordedat the reproducer 43. A switch 44 connects either of these two sourcesto an amplifier 45 whose outvis located near the roof or under thechassis so as to be in a fairly strong field. Since traffic is passingin both directions along a given roadway, the inductive loop is confinedto one-half of the roadway to avoid transmitting thesame directions toboth traific lanes. The receiving loop is continually excited as long asit is in the loop area, and outside of the loop area the loop fieldrapidly decreases.

The traffic information may also be transmitted to the automobile bymeans of infra-red light. As shown in Figs. 11 and 11a an infra-redlight radiator controlled by the modulating source 50, transmits signalsdirectly to the automobile 5|. The light is received by a photocell orother known device 52. It is also possible to use other types of lightto which the eye is not highly sensitive, such as visible red or blue,as long as the light is not of sumcient intensity as to be distracting.

To concentrate the light beam and to filter out unwanted light, thelight source and the receiving device may be placed in housings oi' thetype shown in Fig. 12. In this figure a light source 53 is placed at thefocus point of a parabolic reflector 54. A lens 55 further aids inconcentrating the light rays into a parallel beam. A filter 50 isinterposed between the light source 53 and the lens 55, and this filterpasses only a very narrow band of light of the color which it is desiredto use. Thelight sensitive device 51 is contained in a similar housingas shown at the right of the figure. A lens 50 focuses the light on thedevice 51 and a filter -59 having the same color characteristic as thefilter 50 restricts the received light to only the color which iscarrying the trafilc information.

'While in the embodiments thus far described I have shown the radiatorslocated at the intersections, it is evident that the radiators may beplaced at any point along a highway. The radiators may, for example, belocated at points of hazardous driving to warn of dangerous curves,

etc. The information given out may alternatively describe points of,interest. Such auto radio road information service would be importantto advertisers, and objectionable signboards could be removed andreplaced by this convenient sort of information service. In these lattercases one transmitter and radiator may radiate energy to a plurality oftrafilc lanes.

As an example of an application of my invention, a driver' approachingfrom the left along route 1, such as in Fig. 13, and nearing the firstintersection, would hear from his receiving apparatus "route 1 straightahead-route 3 right route 2 left, or reduce speed-route junction ahead.If the driver continued along route 1 at the next junction he might hearroute 5, Worcester, Springfield, left-route 1, Hartford, New York,straight ahead." Similar information could be given out at the variousother junctions illustrated in Fig. 13.

It is sometimes necessary to change the information given out due toweather conditions, road repairs, etc. The record may then be changed,dependent upon the conditions prevailing, or if the change ininformation is cyclic one or more reproducers may be provided, as shownin Fig. 14. In Fig. 14 three reproducers, each of which has a differentrecording, or serves as a replacement reproducer, has a plug attachedwhich may be inserted in the jack of amplifier to change the recordingbeing transmitted.

It a magnetic recorder and reproducer is used, a. double plugarrangement or the type shown in Fig. may be used to change therecording. A multi-sleeve double plug 63 is connected to a recordingamplifier 84, a source of wipe out voltage 55, and a pilot lamp (notshown). With the plug removed from the jack the reproducer is connecteddirectly to the transmitting amplifier. When the plug is inserted, thereproducer is disconnected from the transmitting amplifier and therecording amplifier is connected to the input of the reproducer. Thelower half of the double plug 53 connects a wipe out voltage to thereproducer wipe out coil and a pilot lamp to the circuit operated by cam66. Cam 66 revolves once for each revolution of the recording tape, andindicates by closing the contacts 61 and operating the lamp that .therecording tape is in the correct position for recording. Closing theswitch 68 for a short period preceding the recording process removes theold recording from the recording tape.

In the preferred form there will be one reproducer for each of theroutes approaching the route junction, and as many other reproducers asis necessary to take care of any emergency. Although each of thereproducers may have a difierent recording, a change in one recordingwill often aifect all of the recordings, that is, when the directionsconcerning one route are changed to provide for a detour, it is usuallynecessary to change the directions concerning the other associatedroutes. To facilitate the simultaneous changing of information forseveral interrelated routes and. to make certain that the directiongiven out by a transmitter cannot be changed from normal withoutsuitable changes in the directions given out by any other transmitterlocated at the same junction, I have provided the interlocking switchingarrangement of Fig. 16. In this figure it may be seen that the output ofeach of the normal reproducers A, B and C is connected to a pairofswitch contacts associated with each of the keys A, B and C. Theemergency reproducers of the groups 69, ill and H3 are respectivelyconnected to the lower contacts of keys A, B and C. The keys operatetheir upper and lower contacts simultaneously, and when the uppercontacts are closed, thelower contacts are open, or vice' versa. Withthe switches in the position shown the information contained on therecording of the normal reproducers is conveyed to the respectiveamplifiers. If, for some reason, itis necessary to change over from therecording of the normal reproducers 'to the recording of the reproducersin any one of the groups, a key, for

example, key A, is thrown. In this new key position the output of allthe normal reproducers are removed from the amplifier inputs, and theoutput of the reproducers in group 69 are connected to the amplifier. Ina similar manner, by leaving key A in its normal position and throwingeither key B or C, the reproducers of groups Ill and 3 may be connectedto the amplifier. Since changes in the directions concerning any oneroute will usually produce changes in directions concerning the otherroutes that may be predetermined, the recording of the emergencyreproducers may be prepared in advance, or the recordings may be madewhen the emergency condition arises. In any event, when the directionsconcerning one route is changed by throwing a key, the directionsconcerning the other associated routes will also be changed, and it therecordings in the emergency group are predetermined and prepared, thecorrect directions for each of the routes are then automatically andsimultaneously switched onto the transmitting amplifiers. Thisinterlocking switching arrangement may be extended to include a largernumber of groups or reproducers or a larger number of reproducers in agroup with modifications apparent to those skilled in the art. a

In Fig. 1'7 I have shown a switching arrangement for optionallyrecording. monitoring or transmitting. This switching arrangement may beused in conjunction with the interlocking switches of Fig. 16 as shown,but is not necessarily restricted to use therewith. With switch II inthe position shown. any reproducer is ready to transmit and thereproducer is selected by means of the interlocked switches. If it isdesired to change the recording on anyone of the reproducers l or 2, asuitable wipe-out voltage is applied to that reproducer and switch ll,corresponding to that reproducer, is moved to the left. Switch 12 ismoved to the recording position and the desired information is impressedupon the recording tape by means of the microphone I3 and the amplifierll. After the recording is made, switch 12 is moved to the monitorposition and by listening to the reproduction through amplifier l5 andspeaker 16 it is possible to aflirm the recording made. By the sameprocess any recording that has previously been made may also be listenedto in order to ascertain its condition or information. When it is foundthat he recording made is correct, the switch H is returned to itstransmit position, and the reproducer is ready for operation as atrafilc director.

While in the above cases I have described the reproducing andtransmitting apparatus as being at the junction point, it is possible tolocate all the apparatus at a central control point and convey theinformation to the radiators by means of connecting lines. In someinstallation of this sort it is then possible to use one reproducer andone recording for several junctions provided similar directions are tobe given out at the different junctions. Connecting the apparatus to theradiators in this latter manner requires a considerable number of linesunless some sort of carrier system is utilized. A carrier system issomewhat objectionable since it requires apparatus not as readilyconstructed as that in the further embodiments of my invention.

In a preferred embodiment of my invention I locate the reproducers andthe transmitting apparatus at a desired junction'point and select andremotely control the reproducing and transmitting apparatus by means ofwell known telephone dialing apparatus as shown in Fig. 18. A telephone15 located at they control center controls a junction selector 16, agroup selector l1, and a group of reproducer selectors I8. A telephoneline, or a power line over which carrier control currents may betransmitted connects the junction selector .to the group selectors, thegroup selectors being located at the Junction point. The group selectorI1 selects one of the group of reproducer selectors 18 or a telephone 19which may be used in conjunction with proper circuits for two-wayconversation between the control center and the junction. The reproducerselector 18 connects one of the reproducers to its respective amplifier.In addition to this means of selecting the desired reproducers at anumber of junctions, the starting and stopping the operation of thetransmitter may be accomplished by dialing designated digits at thecentral control point. At the control center the first digit dialedselects the proper trunk to the desired road junction, the second digitselects the desired group at the road junction, and the third digitselects the desired reproducer in the group and connects it to itsrespective amplifier. When the telephone is hung up by the operator atthe control center a special key or the reproducer selector keeps thereproducer connected to its amplifier and the junction selector andgroup selector return to their home position. I If the reproducerselectors 18 of Fig. 18 are to keep a reproducer connected to itsrespective amplifier after the telephone at the control center has beenhung up or replaced to its normal position, the reproducer selectorcannot be of the ordinary homing type. In Fig. 19 I have shown areproducer selector that will remain in its dialed position after thetelephone at the control center has been replaced. A slow acting relay8| does not operate when the selector arms of the group selector l! arepassing over their contacts but when the group selector finally reachesits dialed position, relay 8| pulls the relay armature 82 to the downposition. This action of armature 82 closes the circuit of relay coil 83and opens the pawl 85 allowing the selector arms 86 to return to a homeposition. At the home position the circuit of relay coil 81 iscompleted, and the relay armature 84 is pulled to the right, opening thecircuit of coil 83 and allowing pawl 85 to again come into operation.Selector arms 86 are now ready to be dialed into the desired position bymeans of a stepping relay comprising coil 88 and armature 89. When thetelephone is replaced at the control center, the selector arms of groupselector 1! return to their home position and coil 8| releases thearmature 82. The selected reproducer is then connected to its amplifierand coil 98 is energized drawing armature 84 to the left position. Pawl85 bears against its ratchet SI, and the selector arms 86 are held intheir dialed position. The reproducer selector will remain in thisposition until it is again selected by the group selector, and arepetition of the above described action will ensue.

It may also be desirable to monitor the reproducer selected before theinformation of .that reproducer is transmitted. This further feature maybe added to the reproducer selector as shown by Fig. 19. When relay coil8| acting with group selector l1 pulls the armature 82 to the downposition, a pair of contacts associated with armature 82 connect theoutput of the reproducer to the group selector line and hence transmitsthe recording to the telephone at the control end, and thus enables theoperator at the control center to monitor the reproducer'selected. Ifthe reproducer is correct, replacing the telephone at the control centerreturns the armature to the up position and connects the reproducer toits amplifier.

Fig. 20 shows an arrangement of selectors whereby a reproducer that isalready in operation or a reproducer after it is put into operation maybe monitored. In this figure an amplifier selector 92 is also connectedto the output of group selector 11. The output of the amplifier selectormay be connected to any part of the transmitting apparatus, but theoutput is preferably connected to the output of the transmittingamplifier so as to monitor the entire transmitting system. The amplifierselector 92 comes into operation when selected by the group selector I1and remains operative until the telephone at the control center isreplaced when the amplifier selector returns to its home position. Inthis type of monitoring arrangement, as in the others herein described,a high impedance amplifier may be connected in the lines joining thecontrol center and the transmitters and/or at the transmitter to amplifythe output signals of the monitored apparatus before and/or aftertransmission over the connecting lines.

Fig. 21 illustrates a circuit arrangement for recording, monitoring andtransmitting. The first digit of a call from the control center selectsthe proper junction; the second digit selects the desired group; thethird digit selects the desired reproducer; and the fourth digit selectsthe proper reproducer circuit for transmitting, recording, ormonitoring. The operation selector is preferably constructed so that inthe home position the selector arms are connected to the transmittingterminals of the reproducer and the input of the amplifier is connectedthrough the reproducer selector to these terminals. In the secondposition the selector arms are connected to the recording terminals ofthe reproducer with the input of the amplifier disconnected by a relayassociated with the operation selector, and in the third position to theoutput terminals of the reproducer with the transmitting amplifier inputdisconnected. To connect the amplifier input to the reproducer at onlythe home position, it is also possible to add an extra arm or contact tothe operation selector that is operative in only the home position. Withthis form of operation selector, it is possible to record, and monitorat the reproducer without transmitting the information to the roadwayradiators. The reproducer selector shown in this figure performs thesame function as that of Fig. 18, and the amplifier selector is similarto the amplifier selector of Fig. 20.

In any remote control system it is desirable to know that the reproduceror transmitter is in operation. A convenient system for maintaining aconstant check on the reproducers or transmitters in operation is shownin Fig. 22. A map 88 containing a plan view of all the roads or routesunder the control of a particular control center is studded with lampslocated at positions corresponding to the actual positions of thetransmitters, and these lamps are turned on or off by special switchesacting with the operation or non-operation of the transmitters. Sincethere maybe more than one reproducer at each transmitter, a plurality oflamps may be located at the map junctions to correspond to the exactlocation of the transmitters, or lamps may be located behind a singlepilot lens, these lamps giving a different color illumingion for each ofthe individual reproducers. g5

When the reproducers arid transmitters are manually controlled, thelamps of Fig. 22 may be operated by switches simultaneously actuatedwith the manual switches. When lamps are used with the dialingarrangement of Fig. 18, a group selector and reproducer selectorshouldbe provided at the control center to operate in conjunction withthe junction selector and simultaneously reproduce the switchingoperations of the junction point'group selector and reproducer selector.An arrangement of this type is shown in Fig. 23 wherein group selectorI1 and reproducer selector 18' perform operations that duplicate the 13switching actions of group selector I1 and reproducer selector 18 ofFig. 18.

In all of the arrangements herein described it is understood thatadditional switches may be included that operate simultaneously with theautomatic ormanual switches to make any or all of the reproducers oramplifiers operative or inoperative. In the remote control arrangement,while I have described the apparatus as being at fixed definitelocation, it is to be understood that the location of the apparatus isnot restricted but that the apparatus may be located entirely at thecenter controlling point or at the junction point.

While I have described particular embodiments of my invention forpurposes of illustration, it will be understood that variousmodifications and adaptations thereof may be made within the spirit ofthe invention as set forth in the appended claims.

What is claimed is:

1. A system for transmitting signals along highways to vehiclestraveling thereon and receiving said signals on said vehicles,comprising a plurality of signal sources, transmitters of radiofrequency energy connected thereto each comprising a plurality of radiofrequency generators, each of said generators operating at differentpredetermined frequencies and being controlled by one of said sources,radiating means associated with said transmitters for radiating radiofrequency energy substantially only within the width of said highwaysand along a short distance thereof, and receivers on said vehicles forreceiving said energy each comprising a plurality of detector stages,filters connected to the output thereof, each filter passing a differentband of frequencies, an amplifier having an input and output, the inputnormally being connected to one of said filters, a switch forselectively connecting to any one of the remaining filters, automaticswitching means under control of signals passed by the filter selectedby said switch for changing the input connections of said amplifier fromnormal to the output of said selected filter when energy of thefrequency passed thereby is received, and speaker means connected to theoutput of said amplifier.

2. A system for transmitting signals along highways to vehiclestraveling thereon and receiving said signals on said vehicles,comprising a plurality of signal sources, transmitters of radiofrequency energy connected thereto each comprising a plurality ofcarrier frequency generators, each of said generators operating atdifferent pre determined frequencies and being controlled by one of saidsources, and a generator of radio frequency energy modulated by saidcarrier frequency generator, radiating means associated with saidtransmitters for radiating radio frequency energy substantially onlywithin the width of said highways and along a short distance thereof,and receivers on said vehicles for receivin said radiated energy eachcomprising a demodulator stage, band-pass filters connected to theoutput thereof, each filter passing one of said carrier frequencies. adetector and amplifier having an input and output, the input normallybeing connected to one of said filters, a switch for se lectivelyconnecting to any one of the remaining filters, automatic switchingmeans under control of signals passed by the filter selected bysaidswitch for changing the input connections of said amplifier from normalto the output of said sefurther comprises means for rendering saidfurther switching means inoperative in response to receipt of energy ofthe frequency passed by said selected filter prior to receipt of energyof the frequency passed by said normal filter.

4. In a system for transmitting signals along highways to vehiclestraveling thereon and receiving said signals on said vehicles comprisinga signal transmitter, means for rendering said transmitter operative inresponse to signals from said vehicles comprising a transmitter on saidvehicle, a receiver for energy from the transmitter on said vehicle at apredetermined position with respect to said highways and spaced fromsaid signal transmitter, switching means for energizing said signaltransmitter, control means responsive to the output of said receiver foroperating said switching means to energize said signal transmitter, andmeans for maintaining said first mentioned switching means operativeover a predetermined period of time.

5. A system according to claim 4 comprising further switching means formaintaining said first mentioned switching means operative over a secondpredetermined period of time upon the receipt of energy in said receiverduring said first predetermined period.

6. A system for transmitting signals along high.- ways to vehiclestraveling thereon and receiving said signals on said vehicles comprisinga plurality of transmitters, a plurality of signal sources associatedwith each of said transmitters, switching means remotely controlled froma common station for selectively connecting any of the signal sourcesassociated with a transmitter to the input thereof, a plurality ofradiating means associated with said transmitters for radiating energysubstantially only within the width of said highway and along a shortdistance thereof, the energy radiated along one highway havingnegligible effect in other highways and in other portions of the samehighway, receivers on said vehicles for receiving said energy, and meansconnected to the outputs of said receivers for emitting audible signals.

7. A system according to claim 6 wherein the operation of any one ofsaid switching means simultaneously changes each of the signal sourcesconnected to the transmitters.

8. A system according to claim 6 wherein said signal sources compriserecords and reproducing devices and said system further comprisesrecording apparatus, monitoring apparatus, and switching means forselectively connecting said reproducingdevices to said recordingapparatus, monitoring apparatus, and said first mentioned switchingmeans.

9. In a system for transmitting Signals along intersecting highways tovehicles traveling thereon and receiving said signals on said vehiclescomprising a plurality of groups of transmitters and associatedreproducers at each of the intersections of said highways, a system forremote control thereof comprising a controlling center relected filterwhen energy of the frequency passed mote from at leastone of saidintersections comprising impulse transmitting apparatus, intersectionselecting means under control or said impulse transmitting apparatus,group selecting means under control of said intersection selecting meansand operated by said apparatus, and reproducer selecting means undercontrol of said group selecting means and operated by said apparatus forconnecting a predetermined reproducer to its associated transmitter.

10. A system according to claim 9 further comprising a map of saidhighways and intersections and lamps under control of said selectingmeans located on said map in positions corresponding to the locations ofsaid transmitters, said lamps indicating the operating conditions oisaid transmitters.

11. A system according to claim 9 further comprising a map of saidhighways and intersections and lamps under control of said selectingmeans located on said map in positions corresponding to the locations ofsaid groups, said lamps indicating the operating conditions of saidtransmitters and reproducers.

12. A system according to claim 9 wherein said reproducer selectingmeans comprises switching means for disconnecting a reproducer from anassociated transmitter, switching means for connecting a predeterminedreproducer to its associated transmitter, and switching means formaintaining said predetermined reproducer connected to its transmitterafter said reproducer selecting means is released by said groupselecting means.

13. A system according to claim 9 wherein said controlling centerfurther comprises speech transmitting and receiving apparatus and saidreproducer selecting means further comprises switching means forconnecting the output of said predetermined reproducer to said speechreceiving apparatus prior to connection to its associated transmitterand for disconnecting the output thereof from said speech receivingapparatus upon connection to its associated transmitter.

14. A system according to claim 9 wherein said controlling centerfurther comprises speech transmitting and receiving apparatus and saidremote control system further comprises operation selecting means undercontrol of said reproducer selecting means for selectively connectingsaid speech transmitting apparatus to the input of said predeterminedreproducer, said speech receiving apparatus to the output of saidpredetermined reproducer, and the output of said predeterminedreproducer to said reproducer selector and transmitter. the input ofsaid transmitter being disconnected from said predetermined reproducerupon connection of said speech transmitting and receiving apparatus tosaid predetermined reproducer.

15. In a trafilc signaling system having a transmitter for communicatingwith tramc proceeding through a. predetermined signaling zone, a signalrecord means electrically connected to said transmitter to effectmodulation of said transmitter by audio-frequency signal energyimpressed on said signal record means, a timing device for controllingduration of operation of said signal record means to establish asignaling'cycle of predetermined duration, said signaling cycle beingsubstantially equivalent to the length oi. time required for trafllc tonegotiate the signaling zone, and means electrically connected to saidtransmitter for establishing a. definite signaling field primarilyembracing the signaling zone.

16. In a. traflic signaling system, a carrier wave transmitter,automatic means for modulating carrier wave energy from said transmitterby prerecorded audio-frequency signal energy, said modulating meansincluding a magnetic signal record device having a strip record-bearingmedium of endless loop type and having a magnetic signal record pickupand amplifying means cooperatively associated therewith, said magneticrecord device having circuits normally operative to eilect automaticrepetitive transmission of recorded intelligence in a transmitting cycleof predetermined duration, and electric switching means under control ofan electric timing mechanism having a control period of predeterminedduration for connecting circuits of said magnetic record device toeflect obliteration of a magnetic signal record on said record bearingmedium concurrently with the recording of a new signal record on saidrecord-bearing medium, said control period being initiated by manuallyoperable switching means interconnected with said electric switchingmeans and said electric timing mechanism, said control period beingautomatically terminated by said electric timing mechanism.

WILLIAM H. CAPEN.

REFERENCES CITED The following references are of record in the HalsteadIII Sept. 9, 1941

